Prince Harry opened up about quitting the royal family, fatherhood, his vision for the future and their new life in America as he joined James Corden for an open top bus tour around LA.
The Duke of Sussex also had a go at rapping the Fresh Prince of Bel Air theme tune and stunned a complete stranger by asking if he could pop in and use their loo.
The interview is the first time Harry has spoken in depth about his decision to walk away from royal life with Meghan Markle, saying he "did what any husband and father would do".
He also revealed some romantic details about the early days of their relationship and gave adorable updates on their little boy, Archie.
We've had a look over the best lines from his Late Late Show appearance.
Archie's first word
Harry shared his son's first word during the interview, and it's pretty impressive.
While most kids say 'mamma' or 'dadda' first, Archie's was more unusual - crocodile.
After revealing his first word, Harry says "three syllables" before an impressed James replies:"That's a big word."
Harry said: "My son is just over a year and a half. He's hysterical. He's got the most amazing personality."
"He's already putting three, four words together, he's already singing little songs."
Harry claims he didn't 'walk away from royals'
The Duke was quick to correct James when he asked why he had walked away from the royal family.
He replies: "It was never walking away. It was stepping back rather than stepping down.
"It was a really difficult environment, as I think a lot of people saw. We all know what the British press can be like.
"It was destroying my mental health. I was like, this is toxic.
"So I did what any husband and any father would do, I need to get my family out of here. But we never walked away.
"As far as I'm concerned, whatever decisions are made on that side, I will never walk away.
"I will always be contributing. But my life is service, so wherever I am in the world it's always going to be the same thing."
Queen's unusual Christmas present
Ever wondered what the Queen buys her great-grandkids for Christmas?
Well, Harry shone some light on the topic by revealing what the Monarch and Prince Philip sent over last year.
"My grandmother asked us what Archie wanted for Christmas, and Meg said a waffle maker.
"So she sent us a waffle maker for Archie, so breakfast now Meg makes up a beautiful organic mix, in the waffle maker, flip it, out it comes.
"He loves it. And now I have waffles for breakfast, bit of yogurt, bit of jam on top. I don't know if that's the right thing to do. Berries, bit of honey."
But James then interrupts, saying: "Sorry you're glossing over the fact that I cannot for the life of me imagine the Queen ordering a waffle maker to be sent to Santa Barbara. I can't get my head around it."
Harry replies: "I don't even know how to comment on that.
"Archie wakes up in the morning and literally just goes 'waffle?'."
Harry hints The Crown is more accurate than you think
While most royals have said they don't watch The Crown, Harry hints that he has watched it and says it gives viewers an idea about what it's like to be in the royal family.
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He's quick to clarify that it's a work of fiction but says it's "loosely based on the truth".
He added: "They don't pretend to be news, it's fictional but it's loosely based on the truth.
He said: "Of course it's not strictly accurate, but loosely, it gives you a rough idea about what that lifestyle, what the pressures of putting duty and service above family and everything else, what can come from that.
"I am way more comfortable with The Crown than I am seeing the stories written about my family, or my wife or myself," he confessed.
He's not a very good rapper
As they walk up to the Fresh Prince Of Bel-Air mansion, James asks Harry if he knows the words to the famous theme song.
He does, and has a go at rapping but there are a few gaps in the lyrics so James has to step in to help him out.
Meghan's surprise appearance and moving joke
After trying to convince Harry to put an offer in on the Fresh Prince mansion, he says he wanted to ask Meghan and asks: "How do you get hold of the Duchess?"
Finally figuring out Harry's contacts book, James dialled her number and Meghan appeared on the other end of the FaceTime call, looking very glamorous.
"Hey Meghan, now listen, I've got to talk to you about something quite serious, OK?" James warned her.
"Tell me," pregnant Meghan urged him.
As Harry lurked in the background, James went on: "I'm here with the big man, now do you recognise this house? That is the house from The Fresh Prince Of Bel-Air and I think this is where you should live.
"I don't think there's anything cooler. You'd be the Fresh Princess Of Bel-Air!"
Laughing, Meghan asked: "And what did he say?"
"Well of course he dragged his heels - he's already used the bathroom, that's how at home he feels," James told her.
"Well that's wonderful. I think we've done enough moving," Meghan shot back, clearly referring to the couple's 12 months of upheaval after quitting the UK for Canada and then the US.
"Here's what I'll do: I'll put you in touch with the owners, you guys can thrash it out. There's no doubt in my mind that this is where you should be," James went on.
Moving the conversation along, Meghan addressed her husband in the background.
"Haz, how's your tour of LA going?" she asked sweetly.
James interrupted, turning to Harry to ask: "'Haz'? I didn't know we were calling you Haz now."
"Well you're not my wife," the Duke deadpanned.
"He's the worst tour guide in LA. Certainly that I've ever had," he then told Meghan.
"Well I'm the only tour guide you've had so I'm the best and the worst," James hit back. "He's having the best time. All our love," he told Meghan as he hung up.
"'All our love!'" Harry mimicked him laughing.
Prince Philip ends video calls in the most Prince Philip way
Leaving a video call can be a bit awkward, and goodbyes can go on longer than we like.
But not for Prince Philip.
Harry explains that rather than pressing the hang up button and leaving the call, he just shuts his laptop.